VIEW ARTICLE

Physiology and Biochemistry

The Effect of Low-Temperature Pre-Incubation Treatment of Tobacco and Soybean Callus Cultures on Rates of Tobacco- and Southern Bean Mosaic Virus Synthesis. James L. White, Graduate Research Assistant, Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824; Fang-Sheng Wu(2), and H. H. Murakishi(3). (2)(3)Graduate Research Assistant and Professor, respectively, Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824. Phytopathology 67:60-63. Accepted for publication 4 August 1976. Copyright © 1976 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-60.

Tobacco callus cultures inoculated with tobacco mosaic virus (TMV) and soybean callus cultures inoculated with southern bean mosaic virus (SBMV) held for 4 days at 10 C (nonpermissive temperature) and subsequently incubated at 24 C (permissive temperature) revealed a higher rate of virus synthesis than those continuously maintained at 24 C. In infected tobacco callus, TMV infectivity dropped slightly 5 hours after a shift to the permissive temperature, then rose logarithmically for 8 to 24 hours after which a linear increase occurred until 60 hours. In infected soybean callus, SBMV infectivity dropped slightly within 8 hours after a change to the permissive temperature, followed by a logarithmic increase in titer to 20 hours, after which the titer increased less rapidly. The total amount of recoverable TMV or SBMV infectivity at the conclusion of the experiments (120 hours) was equal in temperature-treated or nontemperature-treated callus. The similarities in increase of titer in temperature-treated callus, when compared to synthesis of virus in other plant, bacterial, and animal systems, suggest synthesis is occurring in a synchronous manner or approaching synchrony.